metric vs imperial? something seems off

[Rockin Robbins]

In practice the difference between 2000 yards and a nautical mile is so slight as to have no bearing at all on attack accuracy. Real skippers used 2000 yards/nm and never considered using any other numbers.

So long as your constants are at the same accuracy as your measurements you're going to have valid results. Increasing the accuracy of the constants does nothing to make the results better. Even at 2000 yards, we're more accurate with our constant than we can possibly measure Aob, target speed or target range. The only thing we add by refining the number to 2025 yards is to make calculations more complex and introduce a hundred times more human error. That means significantly more misses, not fewer, by using a more accurate constant.